STEROID-INITIATED EXOCYTOSIS IN HUMAN SPERM

顶体反应（AR）是哺乳动物受精的中心事件 包括精子头部膜的融合和穿孔。的 启动这种胞吐过程的分子事件并不完全 明白这项研究的目的是增加我们对这些问题的了解， 人类精子中的事件。这些研究将在体外进行， 人类精子孵化系统。我的实验室发现黄体酮， 存在于卵泡液中并由颗粒细胞分泌的类固醇激素 和卵丘细胞，可以启动人精子AR， 增加精子[Ca 2 +]。这是特别感兴趣的，因为：1）精子 在人体内， 受精; 2）[Ca 2 +]增加如此之快（< 1分钟）， 可能与类固醇表面受体有关。 这些研究将包括：1）类固醇是否增加[Ca 2 +]在 人精子头部; 2）确定必要的类固醇结构， [Ca 2 +]和AR的增加; 3）帮助确定是否 是否存在质膜类固醇受体; 4）研究 类固醇抑制Na+，K+ -ATP酶和[Ca ~（2 + +）] Mg ~（2+）的可能作用 - ATP酶增加精子头部[Ca 2 +]，从而增加AR。 使用的方法包括：体外培养人精子， 计算机荧光图像分析，透射电子 显微镜，AR的免疫荧光测定， HPLC，（45）Ca-流出研究和（32）P-底物的ATP酶测定。 希望这些研究将使人们更好地了解 人类受精的分子基础，从而引领未来 避孕和治疗不孕症的新方法。在 此外，类固醇通过细胞增加细胞内[Ca 2 +] 表面介导的机制可能与钙离子需要事件有关， 体细胞因此，这些研究也可能是重要的以外， 施肥场。

The acrosome reaction (AR) is a central event of mammalian fertilization involving the fusion and fenestration of sperm head membranes. The molecular events that initiate this exocytotic process are not completely understood. The goal of this research is to increase our knowledge of those events in human sperm. These studies will be carried out with an in vitro human sperm incubation system. My laboratory has found that progesterone, a steroid hormone present in follicular fluid and secreted by granulosa cells and cells of the cumulus oophorus, can initiate the human sperm AR by increasing sperm [Ca2+]. This is of particular interest because: 1) sperm have to pass through the cumulus extracellular matrix during in vivo human fertilization; 2) the [Ca2+] increase is so fast (< 1 min) that a sperm steroid surface receptor may be involved. These studies will include: 1) whether steroids increase [Ca2+] in the human sperm head; 2) determination of the steroid structure necessary for the increase in [Ca2+] and the AR; 3) experiments to help determine whether or not there is a plasma membrane steroid receptor; 4) investigation of the possible role of steroid inhibition of Na+, K+ -ATPase and [Ca2+ + Mg2+] -ATPase in increasing sperm head [Ca2+] and thereby the AR. Methods to be used include: in vitro incubation of human sperm, computerized fluorescence image analysis, transmission electron microscopy,immunofluorescent assay of the AR, HPLC, (45)Ca-efflux studies and ATPase assays with (32)P-substrate. It is hoped that these studies will result in a greater understanding of the molecular basis of human fertilization and thereby lead in the future to new methods of contraception and of treatment for infertility. In addition, the increasing of intracellular [Ca2+] by a steroid via a cell surface-mediated mechanism might have relevance to Ca2+-requiring events in somatic cells. Thus, these studies may also be of importance outside the field of fertilization.